The invention relates generally to devices for, and methods of tightening or loosening the tension in footwear.
During normal use of a shoe, there are long periods where it is desirable that the pressure or tension applied to the foot is soft and comfortable or loose, interrupted by short periods when it needs to feel tight to give the foot good stability. The term xe2x80x9cshoexe2x80x9d in the specification and the claims shall refer to any type of footwear having a sole and a relatively flexible upper. Alternatively tightening and loosening the laces of the shoe can achieve alternative modes of a tight versus a loose fit of the shoe. Normally, a person would want to tighten his or her shoes only once, and not have to re-tighten or loosen them later. Further, individuals who prefer a tight fitting shoe often have to re-tighten the laces of their shoes several times as the laces naturally loosen with use over time.
By way of a specific footwear example, golf shoes must perform two separate and sometimes conflicting functions. One is to comfortably support the golfer""s feet while walking on any kind of terrain, while the other function is to provide the golfer with the necessary foot stability during a swing. Between swings, many players would prefer that their laces were loosely tensioned to allow a comfortable fit. During the swing, however, tightly tensioned laces are desired to reduce foot movement in the shoe and give the foot stability. One way this could be achieved is to tighten and loosen the laces repeatedly. Yet most golfers prefer to tighten their shoes only once, and not have to adjust them before or after swings.
Downhill snow skiers typically want their boots tight for the downhill run which may last only a few minutes (or for some skiers a few seconds); then they must line up for the chair lift for several minutes. What is needed is a shoe with an upper which can be quickly tightened around the wearer""s foot for short time periods without the need for manual tightening of laces or similar devices.
The present invention provides a shoe having at least one elongated shape memory alloy element and an electric circuit which when energized will produce a tightening of the shoe upper around the foot of a wearer. In a preferred embodiment, the shoe in one of a pair of golf shoes and the circuit in the shoe is energized by a switch in the heel that is turned on by the golfer clicking his heels together. Typically the golfer does this prior to each important swing of a golf club. A battery contained in the shoe provides a power source to produce a current in the circuit that heats the shape memory alloy causing it to reduce its length providing the tightening of the shoe uppers.